Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Apr 15;194(8):3594-600.
doi: 10.4049/jimmunol.1403234. Epub 2015 Mar 9.

Relative expression levels of the HLA class-I proteins in normal and HIV-infected cells

Richard Apps  1 , Zhaojing Meng  2 , Gregory Q Del Prete  3 , Jeffrey D Lifson  3 , Ming Zhou  2 , Mary Carrington  4
Affiliations

Relative expression levels of the HLA class-I proteins in normal and HIV-infected cells

Richard Apps et al. J Immunol. .

Abstract

The expression level of HLA class-I proteins is known to influence pathological outcomes: pathogens downregulate HLA to evade host immune responses, host inflammatory reactions upregulate HLA, and differences among people with regard to the steady-state expression levels of HLA associate with disease susceptibility. Yet precise quantification of relative expression levels of the various HLA loci is difficult because of the tremendous polymorphism of HLA. We report relative expression levels of HLA-A, HLA-B, HLA-C, and HLA-E proteins for the specific haplotype A*02:01, B*44:02, C*05:01, which were characterized using two independent methods based on flow cytometry and mass spectrometry. PBLs from normal donors showed that HLA-A and HLA-B proteins are expressed at similar levels, which are 13-18 times higher than HLA-C by flow cytometry and 4-5 times higher than HLA-C by mass spectrometry; these differences may reflect variation in the conformation or location of proteins detected. HLA-E was detected at a level 25 times lower than that of HLA-C by mass spectrometry. Primary CD4(+) T cells infected with HIV in vitro were also studied because HIV downregulates selective HLA types. HLA-A and HLA-B were reduced on HIV-infected cells by a magnitude that varied between cells in an infected culture. Averaging all infected cells from an individual showed HLA-A to be 1-3 times higher and HLA-B to be 2-5 times higher than HLA-C by flow cytometry. These results quantify substantial differences in expression levels of the proteins from different HLA loci, which are very likely physiologically significant on both uninfected and HIV-infected cells.

PubMed Disclaimer

Figures

Fig. 1
Fig. 1. Representative flow cytometry staining of each HLA locus on CD4 cells purified from normal donor 2 and infected in vitro with HIV
(A) After gating the CD3+ CD8- population, CD4 downregulation was used to discriminate infected (CD4-) from uninfected (CD4+) cells in a culture (x-axis). Staining for each classical HLA class-I locus was then measured (y-axis). (B) Relative staining of HLA-A (green), HLA-B (red), HLA-C (blue) and isotype control (black) is shown in separate histograms for uninfected (left) and infected (right) cells from the culture.
Fig. 2
Fig. 2. Peptides unique to each HLA used for quantitation in a mass spectrometry-based assay
Mature protein sequence of each HLA class-I protein present in the individuals studied is shown. Peptides unique to an HLA locus within this individual that were used for quantitation are highlighted: 3 peptides for HLA-A (yellow), 4 peptides for each of HLA-B (green) and HLA-C (blue) and 2 peptides for HLA-E (red). In the HLA-E sequence X represents either R or G.
Fig. 3
Fig. 3. Representative mass spectrometry fragmentation spectrum
The doubly charged HLA-A specific peptide WEAAHVAEQLR, detected for normal PBL donor 1, is shown visualized using Scaffold software. N-terminal b fragment ions are labeled in red, C-terminal y fragment ions are labeled in blue and other fragment ions are labeled in green.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Bashirova AA, Thomas R, Carrington M. HLA/KIR Restraint of HIV: Surviving the Fittest. Annu Rev Immunol. 2011;29:295–317. - PMC - PubMed
    1. Gough SCL, Simmonds MJ. The HLA Region and Autoimmune Disease: Associations and Mechanisms of Action. Curr Genomics. 2007;8:453–465. - PMC - PubMed
    1. Sasazuki T, Juji T, Morishima Y, Kinukawa N, Kashiwabara H, Inoko H, Yoshida T, Kimura A, Akaza T, Kamikawaji N, Kodera Y, Takaku F. Effect of Matching of Class I HLA Alleles on Clinical Outcome after Transplantation of Hematopoietic Stem Cells from an Unrelated Donor. N Engl J Med. 1998;339:1177–1185. - PubMed
    1. Campoli M, Ferrone S. HLA antigen changes in malignant cells: epigenetic mechanisms and biologic significance. Oncogene. 2008;27:5869–5885. - PMC - PubMed
    1. Hiby SE, Apps R, Chazara O, Farrell LE, Magnus P, Trogstad L, Gjessing HK, Carrington M, Moffett A. Maternal KIR in combination with paternal HLA-C2 regulate human birth weight. J Immunol. 2014;192:5069–5073. - PMC - PubMed

Publication types

Substances